Device and method for opening the edge of a tubular knitted article or similar

ABSTRACT

The device comprises: a tubular member (5A; 5B) in which the articles are inserted; a plurality of mobile gripping members (49) mobile between a first closed position and a second open position, arranged on one outlet end of said tubular member; and guiding and orienting means (71, 73) associated to said outlet end of said tubular member, for guiding and orienting the tubular article inserted in said tubular member towards said gripping members.

FIELD OF THE INVENTION

[0001] The invention relates to a device for opening the terminal edge of a tubular article, e.g. tubular knitted articles, such as stockings or socks and the like.

STATE OF THE ART

[0002] The need to open an edge of articles to perform a number of machining operations often arises in the production of socks, stockings, pantyhoses and other tubular knitted articles. These articles are made using knitting machines, typically circular knitting machines, which unload semifinished articles whose starting edge and terminal edge are both open. The terminal edge must subsequently be sewn or linked to close the toe of the article.

[0003] This operation entails arranging the article, previously released by the knitting machien for example into a basket, or other container, onto the sewing machine members. This is usually carried out either by hand or by means of complex mechanical handling systems. Similarly, the article may need to be opened to perform subsequent operations in other circumstances, e.g. to iron socks or pair socks prior to packaging.

OBJECT AND SUMMARY OF THE INVENTION

[0004] Object of the invention is to make a device for easily, reliably and fully automatically opening the end, or edge, of a tubular article, i.e. typically the edge of a sock or stocking.

[0005] According to another aspect of the invention, an additional object is to realize a method for easily, reliably and automatically opening the starting edge of a tubular knitted article, typically a stocking or a sock.

[0006] These and other objects and advantages, which will be clear to those skilled in the art by reading the text that follows, are obtained in practice by a device comprising a tubular member in which the articles are inserted; a plurality of mobile gripping members mobile between a first closed position and a second open position arranged on one outlet end of said tubular member; and guiding and orienting means associated to said outlet end of said tubular member for guiding and orienting the tubular article inserted in said tubular member towards said gripping members.

[0007] The tubular article is thus guided along the tubular member so that the edge of the article reaches the gripping members which open it.

[0008] According to a particularly advantageous embodiment of the device according to the invention, the guiding and orienting means comprise two counterpoised contoured bodies which extend from the respective outlet end of the tubular member towards the inside of the tubular member, said counterpoised contoured bodies reciprocally delimiting a passage for said article. The transversal cross-section of the passage may be elongated to arrange the tubular article with the edge folded and flattened in a predetermined direction, determined by the longitudinal extension of the cross-section of this passage. This facilitates gripping and opening the tubular article by the gripping members. In this case, four gripping members reciprocally arranged at 90° around an axis can be advantageously envisaged. A first pair of gripping members are aligned in the direction of development of the passage of the tubular article and the other two gripping members are aligned in the respectively orthogonal direction.

[0009] According to a possible currently preferred embodiment of the invention, each of said two contoured bodies presents a slanted guiding and orienting surface facing the direction of provenience of said article, the slanted surfaces of the two contoured bodies having opposite slants. For example, the guiding surfaces can present a portion which is essentially flat and a portion which is essentially helical. This shape makes the arriving article turn to arrange it in the required position inside the long, narrow passage delimited by the guiding and orienting means. Additionally, the contoured bodies can each present a flat lateral surface. The two flat surfaces, which are preferably parallel one with respect to the other and to the axis of the tubular member, laterally delimit the elongated transversal cross-section passage of the tubular article.

[0010] In a particularly advantageous embodiment of the invention, each of said two contoured bodies consists of three portions; two lateral portions are integral with a mobile unit with respect to said tubular member and an intermediate portion is integral with said tubular member; said tubular member and said unit being reciprocally mobile, to distance the unit from the outlet end of the tubular member. Advantageously, the mobile unit can present housings for inserting the gripping members.

[0011] According to a possible configuration, the gripping members are carried by an annular structure surrounding the axis of the tubular member and equipped with a movement which is parallel to the axis of said tubular member. Opening members can be arranged on this annular structure to open the edge of the tubular article which has been previously opened by the gripping members. The gripping members can consist, for example, of a plurality of extendible stems which are parallel to the axis of the tubular member. These stems can move parallelly with respect to the axis of the latter to turn the edge of the tubular article inside out on the outer surface of the tubular member.

[0012] In a particularly advantageous embodiment, the gripping members are operated by initially controlling a first pair consisting of two counterpoised gripping members for gripping and opening the tubular article and, after the movement of said first pair, by controlling the movement of the second pair of gripping members, which are reciprocally counterpoised to grip and open the tubular article.

[0013] The gripping members are preferably suction members, but can be made in any other way, e.g. in the form of tongs or other mechanical means.

[0014] In order to suck the tubular article into the tubular member, the tubular member may be advantageously connected to a suction tube whose opening is positioned on the opposite side of said gripping members with respect to the outlet end of said tubular member. However, according to an alternative embodiment, the suction may be directly obtained by means of the gripping members when these are of the pneumatic type. In this case, the outlet end of the tubular member is associated with interception and shutting means, which prevent the tubular article from escaping and prevent the intake of aspirated air from the outside as well. If suction is obtained by means of a suction tube temporarily fitted on the output end of the tubular member, an interception member which prevents the tubular article from penetrating in the suction tube is provided to make the tubular article stop in correspondence with the gripping members. The method according to the invention for opening an end of a flexible tubular article, specifically a tubular knitted article, comprises the following phases:

[0015] pneumatically transferring said article towards one end of a tubular member;

[0016] directing the end of said article in a predetermined position with respect to a plurality of gripping units;

[0017] holding said article with said gripping members in correspondence with the end to be opened;

[0018] opening the gripping members whereby opening said ends of the article.

[0019] Additional advantageous characteristics and forms of embodiment of the device and of the method according to the invention are illustrated in the annexed claims and described in greater detail below.

[0020] In the descriptions that follows, the direction and positioning means of the articles and the members for opening the edge of the articles are described in the context of a particular device intended to close the tip with a particular mechanism for transferring the articles from a first station to a second station and vice versa. This aspect, however, is not binding. It is understood that this invention can be implemented in a different context and inserted in a different device, and may also be intended only to open the article which is later transferred to other types of machinery.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be better understood by ensuing the description and the enclosed drawing, which shows a practical and non limiting embodiment of the invention. More particularly, in the drawing:

[0022]FIG. 1 is a perspective view of the device for turning inside out, transferring and closing a tubular article;

[0023]FIG. 1A shows a perspective view which is similar to the view show in FIG. 1 with parts removed;

[0024]FIG. 2 shows a perspective view of a knitting machine equipped with the device shown in FIGS. 1 and 2;

[0025]FIG. 3 shows a perspective view of the gripping member unit for opening the article;

[0026]FIG. 4 shows a perspective view from a different point of view of the unit in FIG. 3 showing the opening and pressing members for turning the tubular article inside out,

[0027]FIG. 5 shows an isolated perspective view of the means for guiding and orienting the article which is supplied to the device to be opened, turned inside out and closed in the toe area,

[0028]FIGS. 6A and 6B show two perspective views cross-sectioned along two longitudinal, reciprocally orthogonal planes of one of the tubular members with gripping members for opening the tubular article and the means for guiding and orienting the tubular article,

[0029]FIG. 7 shows the effect of the guiding and orienting means on the article arriving in the tubular member,

[0030]FIG. 8A shows a perspective cross-sectional view according to a longitudinal plane of one of the tubular members,

[0031]FIG. 8B shows a perspective view of the terminal part of the pneumatic transfer tube and the tubular member support,

[0032]FIGS. 9A and 9B show two possible positions in which the tubular article can be arranged when it arrives at the end of the tubular member on which it must be turned inside out before the toe is closed at a later stage,

[0033] figures from 10 to 13 show four subsequent phases of the opening operation involving the elastic edge of the tubular article in a cross-section which is orthogonal to the axis of the tubular member,

[0034] figures from 14 to 18 show, in a longitudinal cross-section, successive phases of the reversing operation of the elastic edge of the tubular article on the external surface of the tubular member,

[0035]FIGS. 19 and 20 are longitudinal cross-sections showing two successive phases of the tubular article reversing operation on the outer surface of the tubular member,

[0036] figures from 21A to 21D show four subsequent phases of an operation for aligning the edge of the tubular article,

[0037]FIG. 22 shows the tubular member with the article turned inside out on the outer surface prior to being transferred to the second station where the toe is closed,

[0038] figures from 23 to 28 show, in a longitudinal cross-sectional view, successive phases of the operation of tensioning the article for closing the toe and the beginning of the unloading phase of the article with a closed toe,

[0039]FIGS. 29 and 30 are perspective views cross-sectioned along two reciprocally orthogonal longitudinal planes of a tubular member with guiding and orienting means in a different embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0040]FIGS. 1, 1A and 2 show a device according to the invention applicable to a knitting machine, typically a circular knitting machine, for the production of tubular articles, such as socks, stockings or the like. The device is generically indicated with reference numeral 1 while reference numeral 2 in FIG. 2 schematically indicates a circular knitting machine of the type known per se to which device 1 is combined.

[0041] The device 1 presents a support 3 which carries two reciprocally parallel tubular members 5A, 5B. The support 3 turns on an axis A-A which is parallel to the axis of the two tubular members 5A, 5B. The rotary movement of the support 3 is controlled by an actuator 7 arranged above and carried by a fixed frame 9. The rotary movement can be proceeded by an upwards movement of the support and consequently of the tubular members which are applied to it to avoid the collision (during rotation) with the mechanical parts surrounding the lower end of the two tubular members.

[0042] The support 3 turns by 180° on the axis A-A and the two tubular members 5A, 5B are alternatively positioned in two stations side by side. The movement can be either an alternating movement or an intermittent rotary movement without reversing the direction of rotation.

[0043] Opening means are arranged in the first station where the tubular member 5A is located in FIGS. 1A, 1B. The opening means comprise gripping members and opening means for holding the elastic edge of each article which is supplied into the tubular member in the first station and to open the elastic edge on the outer surface of the tubular member itself. Additionally, means for reversing the tubular article on the outer surface of the tubular member are provided. The union of these positioning members is generically indicated by reference numeral 11 in FIG. 1, while a part of these members has been removed in FIG. 1A for greater clarity.

[0044] Angular orienting means and tensioning means are arranged in the second station, said means being generically indicated by reference numeral 13, to pull the toe of the tubular article to be closed and closing means 15, specifically a sewing machine, for closing the toe of the article by sewing or other operation (e.g. linking).

[0045] The various phases for preparing and for closing the toe of the article will be described in greater detail below.

[0046] The tubular articles made by the knitting machine 2 are supplied to the device 1 via a pneumatic transfer tube 17 presenting a terminal curve 17A arranged at an angle of 90° and facing one first end of the tubular member 5A, 5B which is temporarily in the first station, i.e. the tubular member 5A in the position shown in FIGS. 1, 1A, 2. The pneumatic transfer tube 17 is connected to a conduit 19 leading from the lower part of the needle cylinder of the knitting machine 2. Interception means, generically indicated by reference numeral 21, are arranged between the tube 17 and the conduit 19.

[0047] The suction required for collecting the article made by the machine 2 and discharged from the needles is generated, as described below, through the tubular member 5A or 5B which is temporarily in the first station holding the interception members 21 open.

[0048] The tubular article, after being closed by the sewing machine 15 in the second station is transferred again to the first station and sucked to be removed via a pneumatic unloading conduit 23. For this purpose, the conduit 23 is connected to the pneumatic transfer tube 17 and to a fitting 25 which is in turn connected to a suction device (not shown).

[0049] The article is aspirated from inside the tubular member 5A or 5B in which it is reinserted after closing the toe and transits along the tube 17 and along the conduit 23 to reach a box 27 where it is unloaded in a way which is known per se. In this phase, the interception means 21 are closed. After unloading the finished article, a new article is aspirated through the conduit 19 and the transfer tube 17.

[0050] The device described to this point works as follows. A first article made by the machine 2 is sucked via the conduit 19 and the transfer tube 17 to reach the tubular member 5A. Since the article is made by the machine 2 starting from the elastic edge and ending with the toe, it reaches the tubular member 5A with the elastic edge first and the toe behind, i.e. downstream with respect to the direction of advancement. Having reached the lower end of the tubular member 5A, the article is turned inside out on the outer surface of the tubular member 5A by the members generically indicated with reference numeral 11 and described in greater detail below.

[0051] After being positioned, the support 3 is turned by 180° and the position of the tubular members 5A, 5B is turned inside out, so that the tubular member 5A is in the second station while the tubular member 5B is taken to the first station. Here, the toe of the article is pulled and sewn according to a method which is essentially similar to that described in EP-A-1118700 or the like.

[0052] During the tensioning and sewing operations, another article from the machine 2 is inserted in the tubular member 5B which is temporarily in the first station. The article is turned inside out on the outer surface of the tubular member 5B and is prepared for closing the toe.

[0053] After closing the toe of the first article in the second station and positioning the second article in the first station, the support 3 turns again by 180° to return the tubular members 5A, 5B in the configuration shown in FIG. 1. The first article is sucked and unloaded along the tube 17 and the conduit 23 to permit the introduction of the next article while the toe of the second article is closed in the second station.

[0054] The article can be turned inside out the second time after closing the toe in the first or second station both being equipped with means for performing the operation as illustrated below.

[0055] As described above, it is clear that the device 1 is capable of performing the toe closing operations by working on two articles at the same time in the two stations between which the articles are transferred by mechanism 3, 5A, 5B. In this way, the operations needed to close the two overlap. Consequently, the total time required to close the toe is reduced and the device 1 can close all articles from the knitting machine 2 to which it is combined.

[0056] Figures from 3 to 7 show in detail the members for opening and turning inside out the tubular articles which are individually supplied by the pneumatic transfer tube 17 inside either one or the other tubular member 5A, 5B.

[0057] The assembly of the members 11 is carried by an annular structure 31 which is coaxial with the tubular member 5A or 5B temporarily located in the first station. The annular structure 31 is carried by a slide 33 (FIG. 1, 1A) moving on a vertical guide 36 parallel to the axis of the tubular members 5A, 5B. The annular structure carries a plurality of radially movable pressers 35, each of which is associated with a respective actuator 37 (see FIG. 4 in particular). As better described below, the pressers 35 turn the tubular article inside out on the outer surface of the tubular member 5A or 5B and other auxiliary functions.

[0058] Over the radial pressers 35, the annular structure 31 carries four linear actuators 39, e.g. cylinder-piston actuators, which control the movement of respective sliders 41 moving along guides 43, which are orthogonal to the axis of the tubular members 5A, 5B. Each slider 41 carries a respective pneumatic gripping member. The gripping members of a first pair (reciprocally counterpoised) are indicated by reference numeral 45A, while the gripping members of the second pair are indicated by reference numeral 45B. The movement of the gripping members and the sliders 41 is indicated by the double arrow f41.

[0059] Each gripping member presents a sucking head 47 applied to a first end of a tube 49 whose second end is connected by means of a flexible tube to a suction line. The flexible tubes and the suction line are not shown for the sake of simplicity of the drawing.

[0060] A respective stem 51 (see FIGS. 6A and 6B in detail) is associated to each gripping member 45A, 45B. The stems form opening means for opening the edge of the tubular article opposite to the toe of the article which must be closed.

[0061] Each stem is carried by a slide 53 moving on a guide 55 which is integral with a respective slider 41. Each slide 53 is secured by a traction spring 57 to an appendix 59 which is integral with the respective slider 41 so that the four stems 51 are elastically stressed towards the axis of the annular structure 31 and of the tubular member 5A and 5B for the purposes which will be illustrated below.

[0062] A mobile unit 31 is arranged under the annular structure. The mobile unit comprises the upper end of a suction tube 61 carried by a support 63 vertically movable and controlled by an actuator (schematically referred to by numeral 64) according to the double arrow f63. The tube 61 is connected to a suction source by means of a flexible tube (both not shown in the drawing).

[0063] As clearly illustrated in FIG. 5, which shows the suction tube 61 isolated from the other components of the device, the upper part of the suction tube 61 forms housings for the passage of the gripping members 45A, 45B, indicated by reference numeral 65. Under the housings 65, the suction tube 61 presents an interception member 67 consisting of a grid to stop the sucked tubular articles from penetrating inside the tube.

[0064] Four contoured appendixes, indicated by reference numerals 71A, 71B and 73A, 73B respectively, are made on the suction tube 61 between the four housings 65. The appendixes 71A and 73A are reciprocally symmetric. Similarly, the appendixes 71B, 73B are also reciprocally symmetrical.

[0065] Reciprocally symmetric contoured appendixes 71C, 73C are provided inside each of the tubular members 5A, 5B and shown isolated from the respective tubular member in FIG. 5. The shape of the contoured appendixes 71C, 73C is complementary with respect to the contoured appendixes 71A, 71B, 73A, 73B and integral with the suction tube 61 so that the appendix 71C is inserted between the appendixes 71A, 71B forming a contoured body which shape is symmetrical with respect to that formed by the appendixes 73A, 73B, 73C when the latter are inserted between the appendixes 73A, 73B. The two symmetric contoured bodies are generically indicated by reference numerals 71 and 73 in FIGS. 6A and 6B where they are shown as if they were made of a single part and where the respective tubular member 5A, 5B has been removed to clearly show the shape of the contoured bodies.

[0066] The suction tube 61 is mobile in the direction of the double arrow f63 with respect to the tubular member 5A or 5B which is temporarily in the first station of the device 1 allowing the opening of the tubular article by the gripping members 45A, 45B, as clearly described below.

[0067] The contoured bodies 71, 73 formed by coupling the appendixes 71A, 71B, 71C and 73A, 73B, 73C form means for guiding and orienting the tubular article which reaches the lower end of the tubular members 5A or 5B. For this purpose, the contoured bodies 71 and 73 present three main variously contoured surfaces. Each body presents a first cylindrical surface, indicated by reference S₇₁ and S₇₃, reciprocally, corresponding to the internal cylindrical surface of the tubular member 5A or 5B. Additionally, each body presents a orienting and guiding surface indicated by reference X₇₁ and X₇₃. The development of these surfaces is essentially flat and slanted in the upper area and essentially helical in the lower area. The surfaces X₇₁ and X₇₃ face the end of the tubular member from which the tubular knitted article to be oriented and guided comes. Moreover, each contoured body 71, 73 presents a third flat surface indicated by reference Y₇₁ and Y₇₃ which are parallel one with respect to the other and to the axis of the respective tubular member 5A, 5B defining a passage area of the knitted article with an elongated cross-section in the lower area of the two contoured bodies near the outlet of the tubular member 5A, 5B.

[0068] The conformation of the contoured bodies 71 and 73 orients and guides the tubular article which reaches inside the tubular member 5A or 5B. The effect of the conformation of the contoured bodies 71, 73 on the position of the tubular article is clearly illustrated in figures from 7A to 7F, where FIG. 7A is a perspective view of the two contoured bodies 71, 73 and figures from 7B to 7F are cross-sections according to planes which are orthogonal to the axis of the tubular member 5A or 5B in the positions indicated by references B, C, D, E, F in FIG. 7A. In these figures, reference M indicates the tubular article illustrating a transversal cross-section of the elastic edge of the article itself. In FIG. 7A, the article M is shown with the elastic edge folded in four and orthogonally oriented with respect to the surfaces Y₇₁, Y₇₃. This is one of the possible configurations in which the article can arrive from the pneumatic transfer tube 17. In general, the article M will always arrive approximately folded in this way, but with any angular orientation on the axis of the tubular member.

[0069] Advancing on the contoured bodies 71, 73 according to the arrow fM, the article M collides with the surfaces X₇₁ and X₇₃ and is so forced to turn to assume a turned orientation to a maximum of 90° with respect to the initial orientation, i.e. arranged parallelly to the surfaces Y₇₁, Y₇₃. Regardless of the position that the article M assumes when it interferes with the contoured bodies 71, 73, the surfaces X₇₁, X₇₃ thereof cause the possible rotation to take the article to the final position indicated by reference M1 or to the position which is turned by 180° with respect to this position, i.e. always parallel to the surfaces Y₇₁, Y₇₃ as shown in figures from 7A to 7F. This facilitates opening and turning the articles inside out by means of the previously described members, as illustrated below.

[0070] As appears in FIGS. 6A and 6B and in detail also in FIG. 8A, which shows the upper end of one of the tubular members 5A, 5B, the latter each consists of two coaxial tubular elements, internal and external reciprocally, identified by references 5X and 5Y in FIG. 8A. The tubular element 5X can slide for a short distance inside the tubular element 5Y which is directly supported by support 3. A helical compression spring 6 housed in a gap between the two tubular elements 5X, 5Y tends to stress the internal tubular element 5X upwards, i.e. to project from the top of the tubular element 5Y. The contoured bodies 71, 73 (or more precisely the portions 71C, 73C of them) are integral with the internal tubular element 5X of the respective tubular member 5A, 5B.

[0071] By means of the members illustrated in FIG. 8B and described below, the internal tubular element 5X can be pushed downwards and slide inside the tubular element 5Y whereby overcoming the elastic force of the spring 6.

[0072] For this purpose (see FIG. 8B), the pneumatic transfer tube 17 ends with a telescopically elongating portion 17C presenting a collar 17D. Downwards elongation of the portion 17C is controlled by a pair of cylinder-piston actuators 18, one of which is visible in FIG. 8B while both are visible in FIGS. 1, 1A, 2. By moving the portion 17C downwards, the collar 17D rests on a corresponding collar 5Z, which is integral with the internal tubular element 5X of the tubular member 5A or 5B, which is temporarily in the first station by pushing the tubular element 5X downwards. This makes the internal tubular element 5X slide telescopically with respect to the external tubular element 5Y and pneumatically connects the pneumatic transfer tube 17 to the tubular member 5A or 5B, in order to transfer the article from the machine 2 from the transfer tube 17 to the tubular member 5A or 5B. The relative telescopic sliding function of the tubular elements 5X, 5Y will be clarified in the paragraphs describing the method for turning the tubular article inside out.

[0073] The operation of the device for positioning the tubular article on the tubular member 5A or 5B located in the first station for subsequently closing the toe is illustrated below.

[0074] The operations described below are carried out alternatively on the tubular member 5A and on the tubular member 5B. The operation hereof described are explained with reference to tubular member 5A. We will suppose that the tubular member 5A will receive the tubular article M from the machine 2. The actuator 7 places the support 3 in an angular position so to arrange the tubular member 5A in the position of FIGS. 1, 1A. The actuator 63 moves the suction tube 61 upwards making the appendixes 71A, 71B, 73A, 73B which are integral with it penetrate inside the tubular member 5A to complete the contoured bodies 71, 73 (with the appendixes 71C, 73C). The telescopic portion 17D is lowered to pneumatically connect the tube 17 with the inside of the tubular member 5A. Vacuum is created in conduit 19, the pneumatic transfer tube 17 and the tubular member 5A by means of the suction tube 61 (the interception means 21 are open). As soon as the article being knitted by the machine 2 is completed, it is released by the needles and sucked towards the tubular member 5A. The article is open along both the elastic edge and the toe. It moves along the pneumatic path with the elastic edge forwards and the toe behind.

[0075] The vacuum inside the pneumatic route pulls the tubular article M until it collides against the grid 67 which is integral with the suction tube 61. Thanks to the presence of contoured bodies 71, 73 which form guiding and orientation means, the article reaches the tubular member 5A in any position and when it comes into contact with the grid 67 it is arranged in one of the two positions which are schematically illustrated in FIGS. 9A and 9B which are orthogonal cross-sections with respect to the axis of the tubular member 5A carried out near the gripping members 45A, 45B.

[0076] In advance with respect to the arrival of the article M the gripping members 45A, 45B are positioned as shown in FIGS. 9A and 9B: the counterpoised gripping members 45A are more distanced with respect to the counterpoised gripping members 45B. The members 45A are aligned in the direction corresponding to the greater dimension of the elongated cross-section gap defined by the surfaces Y₇₁, Y₇₃ on the lower part of the contoured bodies 71, 73 while the members 45B are aligned in the direction which is orthogonal to the larger dimension.

[0077] Since the gripping members 45A, 45B are arranged directly over the grid 67, they are in the position where the elastic edge of the sock or other tubular article arriving from the knitting machine 2 is arranged and are capable of gripping this edge to open it and turn it inside out on the outer surface of the tubular member 5A as described below.

[0078] When the article M reaches either one or the other position shown in FIGS. 9A, 9B, suction in the suction tube 61 can be discontinued and the counterpoised gripping members 45B can be reciprocally closed and pressed against the tubular article M as shown in FIG. 10. Having reached this position, suction can be activated through the gripping members 45B so that they can grip the edge of the tubular article in two counterpoised areas. At the same time, the suction tube 61 can be moved downwards and distanced by the actuator 63. In this way, a gap is created around the gripping members 45A, 45B, said gripping members being under the lower-edge of the tubular member 5A.

[0079] The opening movement of the gripping members 45B controlled by the respective actuators 39 thus opens the tubular article M which assumes the position shown in FIG. 11 in the area projecting from the lower inlet of the tubular member 5A.

[0080] Subsequently, the gripping members 45A are reciprocally approached and pressed against the edge of the tubular article M in the area comprised between the two gripping members 45B, as shown in FIG. 12. After pressing the tubular article M between the two front surfaces of the gripping article 45A, the latter are activated by creating inside a suction so that the tubular article is engaged by the members. The following opening movement of the gripping members 45A causes the complete opening of the article M which assumes the position shown in FIG. 13.

[0081]FIG. 14 shows a longitudinal cross-section of the tubular member 5A while opening the elastic edge of the article M. Reference MB indicates the elastic edge of the article and reference MP indicates the toe, i.e. the edge intended to form the closed toe of the article after being closed in the second station of the device 1. FIGS. 15 and 20 show the operations for turning the tubular article M inside out on the tubular member 5A according to the same cross-section.

[0082] In FIG. 15, stems 51 have been inserted inside the open edge MB of the tubular article M. The stems withhold the edge after deactivating the gripping members and the fabric of the edge MB no longer adheres to them. The actuators 39 open the stems 51 as shown by the arrows in FIG. 15 to reach the position shown in FIG. 16. Here the four stems 51 (of which only two appear in the cross-section view) are in such a widely open position that the edge MB of the article M is arranged clear of the inlet of the tubular member 5A. It is not ruled out that the opening operations be carried out by different means, e.g. by a single set of gripping means also of the mechanical type. However, the arrangement herein described is particularly reliable because it avoids accidentally damaging the fabric which forms the article.

[0083] As shown in FIGS. 14 and 15, when opening the edge MB of the article M the internal tubular element 5X is in retracted position, i.e. made to retract along the tubular element 5Y. This is obtained by returning the collar 17D and the portion 17C of the pneumatic transfer tube 17 upwards (FIG. 8B). Conversely, in FIG. 16, the internal tubular element 5X is pushed again in the lower position, i.e. with the inlet aligned with the inlet of the external tubular element 5Y. This movement modifies the position of the appendixes 71C, 73C which are integral with the tubular element 5X with respect to the lower inlet of the tubular member 5A.

[0084] An upwards movement according to the arrow f31 of the annular structure 31 which carries the stems 51 causes the elastic edge MB of the article M to be turned inside out on the outer surface of the tubular member 5A, as shown in FIGS. 17 and 18. The stems 51 are retracted.

[0085] After turning the edge MB of the article M on the outer surface of the tubular member 5A, the radial pressers are pressed against the edge itself and the structure 31 which also carries said radial pressers is additionally moved upwards (see FIG. 19, 20). In this way, the radial pressers 35 move the tubular article M turning it inside out from inside to outer surface the tubular member 5A to also take the edge MP formed by the edges of the toe to be closed on the outer surface of the tubular member. More than one travel of the structure 31 may be needed in the case of long articles in which the open radial pressers 35 are moved downwards and upwards again with the radial pressers 35 closed on the tubular member 5A.

[0086] When the edge MP intended to form the closed toe is taken onto the outer surface of the tubular member 5A, i.e. when the article M has been completely turned inside out and is on the outer surface of the tubular member, a sequence consisting in raising, turning by 180° and lowering the support 3 carrying the tubular member 5A to the second station for closing the toe is performed.

[0087] Preliminarly the edge MP may need to be aligned and taken parallel to the inlet edge of the tubular member 5A. This operation can be performed in the first or the second station and is illustrated in figures from 21A to 21D. In FIG. 21A, the article M is entirely turned inside out on the outer surface of the tubular member 5A and the edge MP intended to form the closed toe is arranged in a casual, irregular retracted position with respect to the terminal edge of the tubular member 5A. The radial pressers 35 are arranged in correspondence with the terminal area of the tubular member under the edge MP and approached to the external surface of the tubular member. They are then lifted to meet the edge MP and make the edge slide upwards for a distance which is sufficient to ensure that the edge MP is resting on all pressers 35 (FIG. 21B). In this way, the edge MP is approximately aligned on an ideal circumference which is on top tangent the radial pressers 35. At this point, the pressers 35 are opened and additionally moved upwards to a height which is immediately over the edge MP (FIG. 21C) and closed to press on the tubular article M. In the following phase, the closed pressers are lowered to align the edge MS with the lower terminal edge of the tubular member 5A in the configuration of FIG. 21D. The process can be controlled, for example by means of optical sensors (not shown). In FIG. 21D, the edge MP is aligned on a plane which is orthogonal with the axis of the tubular member and which contains the lower edge of the tubular member 5A. The procedure for aligning the edge MP could be carried out in the second station with similar radial pressers which are provided in said station for other functions as illustrated below.

[0088]FIG. 22 shows a longitudinal cross-section of the tubular member 5A after the operation consisting in turning the article inside out and aligning the edge MP of the article before rotating the support 3 by 180° which transfers the tubular member 5A to the second station.

[0089]FIGS. 23 and 27 show the operations of tensioning the tubular article in the second station before closing the toe.

[0090] An annular structure 81 which is similar to structure 31 is arranged in the second station and carried by a slide 83 moving on a vertical guide 85 (see FIGS. 1 and 2). The annular structure 81 presents radial pressers 87 which are operated by actuators 89, similar to the radial pressers 35 and the respective actuators 37. The annular structure 81 with the radial pressers which are fitted on it is angularly mobile on its axis coinciding with the axis of the tubular member 5A or 5B temporarily located in the second station. The angular movement is provided by an actuator 90 (FIGS. 1-2).

[0091] In this way, the radial pressers 87 are pressed against the outer surface of the tubular article M, the edge MP of the tubular article can be positioned angularly with respect to the tubular member 5A to take the two edges to be joined to form the closed toe and align them with two slots or grooves 5D diametrically opposed along the terminal area of the external tubular element 5Y from the edge of the latter and visible in particular in FIG. 25. If the tubular member 5A is angularly fixed with respect to the support 3 or if its angular position is known, the angular position of the slots 5D is known beforehand. A photocell or other optical sensor 91 (shown in FIG. 25) can be used to identify the correct angular position of the tubular article M, e.g. by marking by knitting in a thread of suitable color. This angular orientation operation of the tubular article with respect to the tubular member on which the article is fitted can be carried out also in the first station instead of the second. Furthermore, it can be carried out also by turning the tubular member and keeping the article angularly stopped by means of the radial pressers. In general, the angular orientation is obtained, consequently, by reciprocally moving the article which respect to the tubular member where the fixed element can be either one or the other.

[0092] After angularly aligning the tubular article M (FIGS. 23, 24) or during said operation, two brackets 13A belonging to the tensioning means 13 can be introduced inside the tubular member from the bottom (FIGS. 24, 25). After angular positioning, the brackets 13A can be opened (FIG. 26) projecting outwards radially from the tubular member 5A through the diametrically opposite slots 5D to tension the edge MP of the article, as shown in FIG. 26. A subsequent downwards movement of the brackets 13A carries the tensioned edge under the lower edge of the tubular member into an area in which it is sewn by sewing machine 15 or other suitable means, equipped for example with a guillotine in which the fabric of the edge MP penetrates. The closing operation is carried out in a way which is known per se and will not be described herein.

[0093] After closing the toe, the article M can be turned inside out again penetrating inside the tubular member 5A and removed. This operation is carried out again by the radial pressers. In the example shown, since there is only one pneumatic transfer tube 17 used to supply the new articles to be closed and to move the closed articles away, the second operation consisting in turning the article inside out and distancing it are carried out in the first station where the tubular member 5A is returned by a new 180° rotation of the support 3. Consequently, in this case, the radial pressers 35 carry out the second operation consisting in turning the article inside out while an upwards suction is generated inside the tubular member 5A. FIG. 28 shows the initial phase of the second inside out turning operation which is obtained by one or more alternating strokes of the radial pressers 35 until the elastic edge MB is sucked into the tubular member 5A.

[0094] The possibility of unloading the closed articles in the second station is not excluded. For example, a suction conduit similar to the transfer tube 17 can be provided and arranged over the transfer means in line with the tubular member 5A or 5B which is temporarily in the second station. In this case, the second operation consisting in turning the tubular article inside out after closing the toe is carried out in the second station by means of the radial pressers 87.

[0095] Naturally, in this case, the distribution of the various phases between the two stations will be different. In any case, the sequence will entail that the operations of opening the elastic edge MB and closing the toe MP must necessarily be carried out in two different stations, i.e. in the first station and in the second station. The remaining operations on the other hand can be carried out in either one or the other of the two stations and distributed according to the need or choice of the operator, always considering the need to minimize the total time needed to close the toe. Particularly, the angular orientation of the article (FIGS. 23, 24) can be carried out in the first station in which case the annular structure 31 will be angularly mobile. Alignment of the edge MP (FIGS. 21A-21D) can in principle be carried out by means of the radial pressers 87 in the second station. As mentioned, the second operation consisting in turning the article inside out and unloading it could be carried out in the second station.

[0096]FIGS. 29 and 30 show a different embodiment of the device according to two cross-sectional views which are similar to the cross-sectional views shown in FIGS. 6A and 6B. The same reference numbers indicate parts which are the same or correspond to those in FIG. 6A, 6B. This second embodiment differs from the previous one for the different configuration of the guiding and orienting means upwards with respect to the gripping means. In this case, the terminal portion (lower) of the tubular members 5A, 5B consists of an internal frusto-conical surface 101 which guides the elastic edge MB of the tubular article towards four cylindrical surfaces 103 which are arranged in correspondence with the gripping members 45A, 45B. In this way, the edge of the tubular article is tightened on the axis of the other tubular member and is gripped by the gripping means. The solution is less advantageous than the previous one because the position in which the tubular article is arranged is not determined and several repeated movements of the gripping members 45A, 45B may be needed for opening it.

[0097] The second embodiment differs from the previous one also because in the first embodiment a collar 8 is provided to reduce the cross-section of the tubular member 5A, 5B. The collar presents a contoured lead-in cross-section to facilitate the passage of the tubular article. This prevents the article from colliding into the contoured bodies 71, 73, and by restricting the incoming product, arranges it for the subsequent orientation.

[0098] It is noted that the drawing is provided by the way of an example only and that numerous changes can be implemented to the construction and embodiments of the invention herein envisaged without departing from the scope of the present invention. The presence of reference numerals in the annexed claims has the purpose of facilitating comprehension of the claims with reference to the description and does not limit the scope of protection represented by the claims. 

1. A device for opening an end of a flexible tubular article, specifically a tubular knitted article including a tubular member (5A; 58) in which the articles (M) are inserted; a plurality of gripping members (45A; 45B) mobile between a first closed position and a second open position, arranged on one outlet end of said tubular member; and guiding and orienting means associated to said outlet end of said tubular member, for guiding and orienting the tubular article inserted in said tubular member towards said gripping members, characterized in that: said guiding and orienting means comprise two counterpoised contoured bodies (71, 73) which extend from said outlet end of the tubular member towards the inside of the tubular member, said counterpoised contoured bodies reciprocally delimiting a passage for said article and presenting a slanted guiding and orienting surface (X₇₁, X₇₃) facing the direction of provenience of said article, the slanted surfaces of the two contoured bodies having opposite slants; and that each of said slanted surfaces present a portion which is essentially flat and a portion which is essentially helical.
 2. Device according to claim 1, characterized in that said passage presents an elongated transversal cross-section.
 3. Device according to claim 1, characterized in that four gripping members (45A; 45B) are reciprocally arranged at 90° around an axis.
 4. Device according to claim 2, characterized in that two of said gripping members, reciprocally counterpoised, are aligned according to a direction which is essentially parallel to the larger dimension of the transversal cross-section of said passage and that the other two gripping members, reciprocally counterpoised, are aligned according to a direction which is essentially orthogonal to said greater dimension.
 5. Device according to claim 1, characterized in that said two contoured bodies present two flat lateral surfaces (Y₇₁, Y₇₃) laterally delimiting said elongated transversal cross-section passage.
 6. Device according to claim 5, characterized in that said flat lateral walls of said contoured bodies are essentially parallel one with respect to the other and to the axis of the tubular member.
 7. Device according to claim 1 characterized in that each of said contoured bodies presents a lateral surface (S₇₁; S₇₃) which is essentially cylindrical, whose shape corresponds with the shape of the internal surface of the tubular member.
 8. Device according to claim 1, characterized in that each of said two contoured bodies consists of three portions; two lateral portions (71A, 71B; 73A, 73B) being integral with a unit (63) which is movable with respect to said tubular member, and an intermediate portion (71C, 73C) being integral with said tubular member; said tubular member and said unit being reciprocally mobile, to distance the unit from the outlet end of the tubular member.
 9. Device according to claim 8, characterized in that said mobile unit presents housings (65) for inserting said gripping members (45A, 45B).
 10. Device according to claim 9, characterized in that said mobile unit presents two of said seats for the gripping members arranged between the two portions which are integral with said unit of each of said two contoured bodies, each of said two housings being additionally delimited by the respective portion, integral with the tubular member, of the respective contoured body when the mobile unit is closed on the outlet end of said tubular member.
 11. Device according to claim 1, characterized in that said gripping members (45A, 45B) are carried by an annular structure (31) surrounding the axis of the tubular member and equipped with a movement which is parallel to the axis of said tubular member.
 12. Device according to claim 1, characterized in that opening members are provided to open the edge of said tubular article.
 13. Device according to claim 12, characterized in that said opening members comprise stems (51) extending in a direction which is essentially parallel to the axis of said tubular member.
 14. Device according to claim 11, characterized in that said opening members are carried by said mobile annular structure (31).
 15. Device according to claim 13, characterized in that it comprises a number of said stems (51) which is the same as the number of the gripping members (45A, 45B).
 16. Device according to claim 13, characterized in that said stems are equipped with a movement between a first reciprocally closed position and a second open position.
 17. Device according to claim 16, characterized in that movement of said stems between said first and said second position is essentially parallel with respect to the movement of said gripping members between their respective first and second position.
 18. Device according at least to claim 11, characterized in that said gripping members are fitted on sliders (53) which slide on guides (55) integral with said mobile annular structure, said sliders being operated by respective actuators.
 19. Device according to claim 14, characterized in that said stems are elastically connected to said sliders.
 20. Device according to claim 19 characterized in that said gripping members are operated with movements which are displaced at least in part.
 21. Device according to claim 3, characterized in that said gripping members (45A, 45B) are operated by initially controlling a first pair consisting of two counterpoised gripping members for gripping and opening the tubular article and, after the movement of said first pair, by controlling the movement of the second pair of gripping members, which are, reciprocally counterpoised to grip and open the tubular article.
 22. Device according to claim 16, characterized in that said stems are operated in a coordinated fashion with the movement of said second pair of gripping members to be taken inside the article withheld by said gripping members and subsequently opened.
 23. Device according to claim 1, characterized in that said gripping members are suction members.
 24. Device according to claim 1 characterized in that said tubular member may be connected to a suction tube (61) whose inlet is arranged on the opposite side of said gripping members with respect to the outlet end of said tubular member.
 25. Device according to claim 24, characterized in that it comprises means (67) of intercepting the tubular article between the gripping members and the inlet of the suction tube.
 26. Device according to claim 8, characterized in that said suction tube (61) is connected to said mobile unit (63).
 27. Device according at least to claim 11, characterized in that said mobile annular structure (31) carrying said gripping members (45A; 45B) comprises radial pressers (35) for engaging said article and making it slide on the outer surface of said tubular member (5A, 5B) with a movement of said mobile annular structure with respect to said tubular member.
 28. Device according to claim 27, characterized in that it comprises sensors for verifying that the article has been gripped by said gripping members.
 29. Device according to claim 11, characterized in that said tubular member is formed by two tubular elements (5X, 5Y) inserted one inside the other and reciprocally axially mobile, at least part of said guiding and orienting means being integral with the innermost tubular element.
 30. Device according to claim 29, characterized in that the outermost tubular element presents slots developing from the edge of the outlet end in parallel to the axis of the tubular member.
 31. Device according to claim 1, characterized in that a collar (8) for reducing the passage cross-section of the tubular member (5A, 5B) is arranged inside said tubular member, upstream to said guiding and orienting means with the direction of advancement of the tubular article.
 32. Method for opening an end of a flexible tubular article, specifically a tubular knitted article, comprising the following phases: pneumatically transferring said article towards one end of a tubular member; directing the end of said article in a predetermined position with respect to a plurality of gripping units; holding said article with said gripping members in correspondence with the end to be opened; opening the gripping members whereby opening said ends of the article, wherein said end edge of the article is oriented to assume a conformation which is approximately orthogonal to a first direction of reciprocal alignment of a first pair of said counterpoised gripping members, a second pair of gripping members are aligned and counterpoised along a second direction, essentially orthogonal to said first direction, and said article is engaged by said first pair of gripping members and stretched along said first direction, while the gripping members of the second pair are held distanced from the article; and in which the gripping members of the second pair are subsequently approached to the article, gripping the article and stretching it in said second direction.
 33. Method according to claim 32, comprising the following phases: inserting a plurality of opening means in the open end of said article; tensioning the article in correspondence with its end by said opening means; turning the end edge of the article inside out by means of said opening means on the outer surface of said tubular member.
 34. Method according to claim 33 comprising the phase of turning the entire article inside out on the outer surface of said tubular member.
 35. Method according to claim 32, in which said gripping members pneumatically engage the article.
 36. Method for opening an end of a flexible tubular article, specifically a tubular knitted article, comprising the following phases: pneumatically transferring said article towards one end of a tubular member; directing the end of said article in a predetermined position with respect to a plurality of gripping units; holding said article with said gripping members in correspondence with the end to be opened; opening the gripping members whereby opening said ends of the article.
 37. Method according to claim 36, comprising the following phases: inserting a plurality of opening means in the open end of said article; tensioning the article in correspondence with its end by said opening means; turning the end edge of the article inside out by means of said opening means on the outer surface of said tubular member.
 38. Method according to claim 37 comprising the phase of turning the entire article inside out on the outer surface of said tubular member.
 39. Method according to claim 36, in which said end edge of the article is oriented to assume a conformation which is approximately orthogonal to a first direction of reciprocal alignment of a first pair of said counterpoised gripping members, and wherein a second pair of gripping members are aligned and counterpoised along a second direction, essentially orthogonal to said first direction.
 40. Method said first pair of gripping members and stretched along said first direction, while the gripping members of the second pair are held distanced from the article; and in which the gripping members of the second pair are subsequently approached to the article, gripping the article and stretching it in said second direction.
 41. Method according to claim 36 in which said gripping members pneumatically engage the article. 